Center and key-seating square



(No mm.)

. J. B. PRICE. CENTER AND KEY SEATING SQUARE.

No. 477,959. Patented June 28, 1892.

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UNITED STATES PATENT OFFICE.

JOHN B. PRICE, OF WVOLLASTON, MASSACHUSETTS.

CENTER AND KEY-SEATING SQUARE.

SPECIFICATION forming part of Letters Patent No. 477,959, dated June 28,1892.

Application filed March 30, 1892. $erial No. 427,111. (No model.)

To all whom, it may concern.-

Be it known that I, JOHN B. PRICE, a citizen of the United States, and aresident of Vollaston, in the county of Norfolk and State ofMassachusetts, have invented certain new and useful Improvements inOenter-Sguares; and I do hereby declare the following to be a full,clear, and exact description of the invention, such as will enableothers skilled in circle, and to indicate perpendicular lines through acylindrical body, with the base resting on either a horizontal orcylindrical surface. With these and other ends in View the inventionconsists of a base having its two arms arranged at right angles to eachother, (or at an angle of ninety degrees,) and one of said arms having alongitudinal slot, which opens through both faces of the slotted arm,and a blade provided with an enlarged head lying at an angle offorty-five (45) degrees to the axis of said blade and adapted to befitted in the longitudinal seat'in either the inner or outer face of theslotted arm of the base, said head of the blade having a projectingthreaded stud, which passes through the slot and receives athumb-screw'to bind against the slotted arm to hold the blade securelyin its adjusted position on the slotted arm.

The invention further consists in the construction and arrangement ofparts, which will be hereinafter fully described and claimed.

In the accompanying drawings, Figures 1, 2, and 3 are side elevations ofthe center square, showing the blade adjusted in diiferent positions orangles. Fig. 4 is a front elevation with the blade adjusted as in Fig.1.

Fig. 5 is a horizontal sectional View on theline 00 a: of Fig. 4.. Fig.6 is a detail view of a part of the blade, showing its threaded stud andthe thumb-nut. Figs. 7, 8, and 9 illustrate the method of using thebevel on a cylindrical shaft.

Like letters of reference denote corresponding parts in the severalfigures of the drawings.

. The improved center-square consists of three parts-the base A, a blade13, and a thumbnut O for holding the blade firmly in place on theslotted arm of the base. This base is made or cast in a single piece ofmetal, and it comprises two arms a 0., arranged at an angle of ninety(90) degrees to each other to form a right angle. One of thearlns a ofthe right-angled base is provided with a central longitudinal slot d,which extends from the junction of the two arms nearly to the outer endof the arm a, as shown in Fig. 4., and in the opposite faces of theslotted arm a are formed or out two seats e f, respectively.

The blade B is made of a single fiat piece of metal of suitable lengthand width, and at one end the blade has an enlarged head 9, formed bythe two laterally-extending flanges, said head being of such width thatit is adapted to fit snugly in either of the seats 6 f in the oppositefacesof the slotted arm a. The head 9 lies at an angle of forty-five(45) degrees to the longitudinal axis of the blade, and from the headprojects a rigid threaded stud D,

which is at a right angle, or an angle of ninety (90) degrees, to thehead on said blade. The head g fits snugly in the seat on either theillner or outer face of the slotted arm a and the stud passes throughthe slot in said arm, the blade being held in position by the thumbnutO, which is screwed on the threaded stud D and binds against the slottedarm of the base A. p

The implement is designed for use particularly on cylindrical shafts,and in Figs. 1 and 7 I have shown the-blade adjusted for use indetermining the center of the shaft. The blade is adjusted or fittedbetween the arms of the base and the thumb-nut binds against the outerface of the slotted arm a. The blade is adjusted so that one edgethereof is at an angle of forty-five degrees with the inner angleformed. by the arms a a, and the imple= ment is placed around the shaftor other cylindrical surface so that its arms rest upon the shaft, asshown in Fig. 7. By scribing the lines at right angles to others acrossthe end of the shaft in the manner shown in Fig. 7 the intersectionof'the lines indicate the center of the shaft.

To determine the lines for cutting a key way or seat in the shaft, theblade can be adjusted on the slotted arm a for a distance from the angleequal to one-half the width of the key-seat. After the central line ofthe way or seat has been drawn the base is adjusted around the shaft, sothat one side of the way can be drawn along the edge of the blade, andthe base is then reversed and the other side of the way or seat can bescribed along the same edge of the blade, as will be readily understoodby reference to Fig. 8. The inner and outer faces of the arm a and oneedge thereof are suitably inscribed with the scale in inches and thesubdivisions thereof, so that the space between the inner edge of theblade and the angular center of the base can be readily determined.

The blade can be adjusted on the slotted arm a a suitable distance fromthe angular center of the base and the implement moved around the shaftto draw or scribe chords of a circle, as indicated in Fig. 9.

To indicate an angle of forty-live degrees from the horizontal, theblade should be fitted in the seatfon the outside of the arm a, and thearm a should be placed on a bevel surface, as shown in Fig. 2; but toindicate a perpendicular to the horizontal the blade should be reversedand the base inverted, so that the beveled ends h h of the arms a a, canrest true on the level surface.

The device is extremely simple in construction, can be manufactured verycheaply, and is reliable and efficient in service.

It is evident that changes in the form and proportion of parts can bemade without departing from the spirit or sacrificing the advantages ofthe invention.

W'hat I claim as new is 1. A bevel consisting of a right-angled basehaving the two rigidly-joined arms and one of its arms slottedlongitudinally, an adjustable blade fitted in said slotted arm, andmeans for clamping said blade rigidly to the arm, as and for the purposedescribed.

2. A bevel comprising a right-angled base having its two arms made in asingle piece and with one of said arms provided with a longitudinal slotand a blade arranged or held at an angle of forty-five degrees to saidslotted arm and adj ustably clamped thereon, as and for the purposedescribed.

3. A bevel comprising a right-angled base having one of its arms slottedlongitudinally and provided with parallel seats on both the inner andouter surfaces thereof, a blade adapted to be fitted in either seat ofthe slotted arm, and means for clamping the blade rigidly to said arm,as described.

4:. A bevel comprising a right-angled base having one of its armsprovided with a seat and a slot, ablade with an angular head which fitsin the seat and carrying a stud that enters the slot, and aclamping-nut, as and for the purpose described.

5. A bevel comprising a right-angled base having one of its armsprovided with a slot, a blade with a right-angled threaded stud adaptedto pass through said slot and having a bearing against one side of theslotted arm, and a thumb-nut screwed on the stud to bear against theother side of the slotted arm, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

JOHN B. PRICE.

Witnesses:

OHAs. F. THAYER, HENRY J. THAYER.

